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George,

As an aside to this discussion, I am wondering what the status of
EBBCO now is.  In about 1972, I set out to find the East Berks Boat
Co. (EBBCO).  After asking several shopkeepers in town, I was
directed to John Weatherlake's home as the most probable location.
There, he showed me how he assembled the sextants in his garage.  My
understanding as of 2 years ago is that they are still in production,
but on a larger scale than his garage could afford, and under
different names than EBBCO.  The name Antares comes to mind, possibly
as Plastimo in France names it.  Anyway, I , and I think some list
members, might be interested to know more about this sextant today.
Any information you may have, as a countryman of Mr. Weatherlake,
will be appreciated.
Ken
On Sep 23, 2008, at 2:36 PM, George Huxtable wrote:

>
> Frank wrote-
>  In some of my recent sextant calibration tests, I've had the
> | pleasure of watching, in real time, the calibration of a plastic
> sextant
> | glide up two minutes of arc postive for a couple of minutes (of
> time) then
> | drift in the opposite direction until it was zero and then
> negative by a
> | couple of minutes of arc. Something like that simply cannot be
> corrected
> in
> | live navigation.
>
> ==========================
>
> That's interesting, and rather a surprise to find such extreme
> bad-behaviour. Was the index error similarly unstable, or did the
> index
> error stay put while the calibration changed? What were the
> conditions of
> the test? Had the instrument been given any time to stabilise, in
> temperature? Presumably, the instrument had been checked-over to
> ensure that
> no mirrors or brackets were at all wobbly
>
> My own experience of plastic sextants has been confined to just one
> make;
> various models of the Ebbco design. And I must say that I've never
> been
> aware of such wild short-term changes in calibration as Frank
> describes.
> Such changes would have been quite apparent, in distorting a
> sequence of
> altitude observations. Nor have I ever been aware of measurable
> drifts in
> index-error, which I have always checked before and after such a
> sequence. I
> would never expect to measure angles to better than an arc-minute
> or so with
> an Ebbco, however.
>
> Frank's comments, applying to an unspecified "plastic sextant", tar
> all such
> sextants with the same brush. It would be fairer, and more useful
> to others,
> for him to actually "name names", and specify the type of plastic
> sextant
> which he found to be so faulty.
>
> George.
>
> contact George Huxtable, now at george@hux.me.uk
> (switched from george@huxtable.u-net.com)
> or at +44 1865 820222 (from UK, 01865 820222)
> or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
>
>
>

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